1. Field Of The Invention
This invention relates to surgical stapling apparatus, and more particularly to a surgical stapling apparatus incorporating a safety shield for protecting extraneous body tissue from the operation of the stapler.
2. Description Of Related Art
Surgical stapling apparatus in which a plurality of surgical fasteners are applied substantially simultaneously to produce an array or surgical fasteners are known. Typically these apparatus include a fastener holder disposed on one side of the tissue to be fastened, an anvil assembly parallel to the fastener holder on the other side of the tissue to be fastened, means for linearly translating the fastener holder and the anvil assembly toward one another so that the tissue is clamped between them, and means for driving the fasteners from the fastener holder so that the ends of the fasteners pass through the tissue and form finished fasteners as they make contact with the anvil assembly, thereby producing an array of finished fasteners in the tissue. The term "fasteners" is used herein as a generic term for metal surgical staples, the staple-shaped portion of one part or two part resinous surgical fasteners, and their equivalents. Similarly, the term "anvil assembly" is used herein as a generic term to include the anvil used to clinch metal surgical staples, the retainer holder and retainer member of two-part resinous surgical fasteners, and the equivalent of these elements.
In common use are devices such as those disclosed in U.S. Pat. Nos. 4,354,628 and 4,665,916. More particularly, U.S. Pat. No. 4,354,628 discloses a surgical stapler apparatus for forming an array of surgical staples in body tissue including an anvil member against which the staples are crimped, and a staple holder pivotally mounted adjacent one end of the anvil member.
U.S. Pat. No. 4,665,916 discloses a surgical stapling apparatus comprising an anvil assembly against which fasteners are formed and a fastener holder pivotally mounted adjacent one end of the anvil assembly, a spacer member at the other end so constructed to displace tissue that would otherwise obstruct the spacer member from properly positioning the fastener holder relative to the anvil assembly to insure proper fastener formation, and a knife assembly to cut the tissue between the rows of formed fasteners.
Surgeons use such devices by selecting, or targeting the body tissue to be fastened, positioning the stapler mechanism so that the target tissue is between the anvil assembly and the fastener holder, then actuating the fastener holder and drive mechanism. In some surgical applications, though, it is possible to have extraneous untargeted tissue enter the gap between the anvil assembly and the fastener holder when the surgeon is positioning the mechanism. If the extraneous tissue is covered by the target tissue the surgeon may inadvertently activate the stapler mechanism and damage the extraneous surrounding tissue. This problem may occur, for example, in caesarean section procedure when fetal tissue may inadvertently enter the stapler mechanism as the surgeon is carrying out the procedure.
Clearly, therefore, there is a need to provide a surgical stapler whereby the extraneous tissue is protected from the operation of the stapler.